When one host fetches the latest flake revision, it publishes to NATS
and all other hosts receive the update immediately. This reduces
redundant nix flake metadata calls across the fleet.
- Add nkeys to devshell for key generation
- Add nixos-exporter user to NATS HOMELAB account
- Add Vault secret for NKey storage
- Configure all hosts to use NATS for revision sharing
- Update nixos-exporter input to version with NATS support
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>